Diving in to everyday discoveries

More –

Dungeness Crab

Many visitors have come by, and there has been much to teach! One of the really cool creatures we have in our touch tank is a small Dungeness Crab.

These dudes are pretty awesome. Being one of the most important food species of the Pacific Northwest, they are a regular sight as people pass by with crab pots and other tackle.

But what fascinates me is not what they end up as, but how they get there! The mating process of the Dungeness Crab is a rather extensive one. Mating usually occurs May and August, when the female crab is ready to molt. The female must molt before she is ready to mate, and her shell will be soft and vulnerable during the process. The male will know she is ready by pheromones present in her urine, and takes her in a protective embrace that can last for several days. Tucked under the male, their abdomens touch, heads face each other, the female will accept his fertilization. Finally, the pair will extract themselves, and the female will extrude eggs from her body several months later, where they remain attached for three to five months. Once they hatch, the baby crabs are free swimming, and go through five larval stages before they reach maturity, which takes about 2 years.

The image above is a mix of megalops and zoa forms of the crab larvae, taken through a microscope in the Olympic Beach Ranger Station.

Dungeness Crabs are very efficient scavengers and hunters, feeding on a wide variety of prey. Feeding on small mollusks, clams, fishes, and other crustaceans, they’ll also take just about anything that dies, including other dungeness crabs. They are preyed upon in each of their stages, from salmon, rockfishes, and large filter feeders as larvae to octopus, seals, large fishes, and humans in their adult stage.

These guys go through a lot before they end up on your plate. So the next time you sit down to a meal of Dungeness Crab, think about the long journey it took, and make sure to purchase them from a sustainable fishery, or better yet, catch them yourselves. Bon appetite!

Thanks for reading, and keep an eye out for more cool species from our touch tank, and always remember to keep swimming.